1. Field of the Invention
This invention relates to an apparatus and method for automatically leveling frames with respect to gravity. More specifically, it relates to using a gravitational reference, such as a bob, to determine a vertical direction with respect to gravity, which is used to adjust the angle of a frame suspended from a wall or ceiling, such as a picture frame, or the like, to make it level. Generally, it provides a convenient, automatic way to keep frames level, even as they tend to move due to environmental disturbances such as bumps, vibrations, moving air currents, and thermal effects.
2. Related Art
Frames that are suspended from walls and ceilings, such as picture frames, when first hung, and at various times thereafter, must be leveled or re-leveled so that the frame is parallel with respect to a reference. Usually, the plane of the floor or ceiling is chosen as a reference for leveling the top or bottom edge of a frame. Most often, visual inspection is used to level frames. Usually, one steps back from the frame after first hanging it, and then, from a distance, views it with respect to the floor, ceiling, or some other reference. Then one returns to the frame and adjusts it manually. Sometimes this process is repeated several times until the frame appears to be level. However, without using an instrument, such as a bubble level or some other instrument, visual inspection can only provide a rough approximation of the level orientation. Furthermore, this process requires that a person manually perform the steps necessary to level the frame.
Various inventors have approached this problem in two general ways: first, by equipping a frame or frame hardware with a level indicator or sensor, and, second, by devising means for easing the manual adjustment of the frame as it is suspended or hung. For example, U.S. Pat. No. 4,208,802, discloses a mounting plate that is attached to a picture frame and which holds a removable and disposable liquid bubble level. After the picture frame is leveled, the invention relies on friction or an adhesive to help keep the picture level. U.S. Pat. No. 4,944,094 describes a picture frame leveling tool that includes upper and lower visual level indicators for enabling the alignment of the picture relative to a supporting wall. PCT Application No. WO98/24085 discloses a picture frame with a spirit level built-in to a recessed portion of the frame. The level is not generally visible by the viewer of the picture, but is visible to the person leveling the picture, who sees it from above. The positioning device of U.S. Pat. No. 4,212,213 is a pivotally mounted indicator arm that is only visible from the front of the picture when the picture needs leveling.
A variety of ways have been devised to ease picture frame level adjustment. For example, U.S. Pat. No. 4,364,538 provides a picture hanging wire cable each end of which is looped through a screw eye on a picture frame, and connected back onto itself through a movable locking aperture. Wire length, and thus picture level, is adjusted manually by sliding either side of the wire cable locking aperture. U.S. Pat. No. 5,743,507 describes a picture hanging rod in association with a wall stud mounted baseplate. The rod has a hanging lug for carrying a suspension wire of a picture, mirror, or the like. The hanging stud can be adjusted through a 360 degree rotation. The adjustable picture hanging hook of U.S. Pat. No. 6,527,244 provides a toothed wheel that is received within a base with locking grooves, and which has an extending knob for hanging a picture. The level of the picture frame is adjusted by removing the picture frame and manually moving the knob an appropriate amount before re-hanging the frame. U.S. Pat. No. 6,062,525 discloses a picture frame hanger that uses two screws and two threaded holders that provide for continuously adjusting the vertical and horizontal position. A screwdriver is used manually to adjust the position of the screws. The picture frame hanger of U.S. Pat. No. 5,947,438 includes a threaded adjuster (U-shaped in cross-section) that receives a picture hanging wire or cord. Various configurations of the device provide for horizontal and vertical movement. The invention of U.S. Pat. No. 4,575,905 is a single piece cleating and clamping device used manually for securing and adjusting the effective length of wire used to hang a picture frame. U.S. Pat. No. 4,463,924 discloses a lockable picture hanging and straightening device for securing a picture to a wall. The device uses a reel and a line of adjustable length attached to a corner of a picture frame and adjusted manually until the picture is level.
None of these references discloses an automatic, self-leveling frame for pictures, mirrors, or other items that are suspended from a ceiling or hung on a wall. More specifically, once hung and leveled manually, none of the inventions of the cited references are able to re-level themselves automatically should they move out of a level orientation. Unlike the present invention, re-leveling in the above cited art requires human intervention.
3. Objects and Advantages
Accordingly, in contrast to the shortcomings and limitations of the related art, the present invention provides an apparatus and method for suspending or hanging a frame, such as for pictures, mirrors, and the like, that is automatically self-leveling with respect to a reference.
Therefore, it is an object of the present invention to provide for the self-leveling of a frame with respect to a reference without relying on a human being to make mechanical adjustments manually as indicated by a level indicator or sensor.
It is a further object of the present invention to simplify the process of leveling a frame, such as for a picture, mirror, and the like, by dispensing with the need for human observation and judgment in the leveling process.
It is a still further object of the present invention to level a picture frame, and the like, with respect to gravity by automatically locking the frame's orientation only when it is in a level position.
It is yet another object of the present invention to level a picture frame, and the like, with respect to gravity and to re-level the picture frame automatically if it should move out of a level position.
It is still another object of the present invention to keep a picture frame, and the like, locked in its orientation only if it is level with respect to gravity, and to unlock its orientation if it moves out of a level position with respect to gravity.
It is yet another object of the present invention to adjust the orientation of a frame with respect to gravity by causing the frame to move under the influence of gravity into a level configuration.